Blockade of nicotinic currents in hippocampal neurons defines methyllycaconitine as a potent and specific receptor antagonist.
Blockade of nicotinic currents in hippocampal neurons defines methyllycaconitine as a potent and specific receptor antagonist.
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发表时间：
1992-04
影响因子：
3.6
通讯作者：
M. Alkondon;E. Pereira;S. Wonnacott;Edson X. Albuquerque
中科院分区：
文献类型：
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作者：
M. Alkondon;E. Pereira;S. Wonnacott;Edson X. Albuquerque
Methyllycaconitine，从种子中分离出的毒素，抑制乙酰胆碱和类毒素诱导的培养胎鼠海马神经元的全细胞电流，在皮摩尔浓度。这种拮抗作用具有特异性、浓度依赖性、可逆性和电压依赖性。此外，methyllycaconitine抑制125 I-α-银环蛇毒素结合到成年大鼠海马膜，保护免受α-银环蛇毒素诱导的烟碱电流的假不可逆阻滞，并转移乙酰胆碱的浓度-反应曲线的权利，在胎鼠海马神经元，这表明这种毒素的可能的竞争性作用模式。显着低浓度的methylycaconitine（1-1000 fM）降低类毒素诱导的单通道开放的频率，没有检测到平均通道开放时间的减少。这些行动的methyllycaconitine赞扬这种神经毒素的表征α-银环蛇毒素敏感的神经元烟碱受体，迄今为止，逃避功能演示亚类。
Methyllycaconitine, a toxin isolated from the seeds of Delphinium brownii, inhibited acetylcholine- and anatoxin-induced whole-cell currents in cultured fetal rat hippocampal neurons, at picomolar concentrations. This antagonism was specific, concentration dependent, reversible, and voltage independent. Furthermore, methyllycaconitine inhibited 125I-alpha-bungarotoxin binding to adult rat hippocampal membranes, protected against the alpha-bungarotoxin-induced pseudoirreversible blockade of nicotinic currents, and shifted the concentration-response curve of acetylcholine to the right in fetal rat hippocampal neurons, suggesting a possible competitive mode of action for this toxin. Remarkably low concentrations of methyllycaconitine (1-1000 fM) decreased the frequency of anatoxin-induced single-channel openings, with no detectable decrease in the mean channel open time. These actions of methyllycaconitine commend this neurotoxin for the characterization of the alpha-bungarotoxin-sensitive subclass of neuronal nicotinic receptors, which has hitherto eluded functional demonstration.